Automatic stop control mechanism



y 1955 H. L. LAMBERT EI'AL AUTOMATIC STOP CONTROL MECHANISM 2 Sheets-Sheet 1 Filed Aug. 12, 1955 NVENTORS HARRY L. LAMB! WILL/AM U. M05175 ATTORNEYS July 31, 1956 H. LAMBERT ETAL AUTOMATIC STOP CQNTROL MECHANISM 2 Sheets-Sheet 2 Filed Aug. 12, 1955 "'w/LL/,4M MOS/16f? ATTORNEYS United States Patent AUTOMATIC STOP CONTROL MECHANISM Harry L. Lambert, West Hartford, and William O. Mosher, Wethersfield, Conn, assig'nors to Royal McBee gorlporation, New York, N. Y., a corporation of New Application August 12,1955, Serial No. 527,970

7 Claims. (Cl. 197-17) This invention relates to automatic stop control mechanism, and more particularly to such mechanism especially suited for interrupting the driving of electric type- Writers or like machines in response to overloading of the driving mechanism caused, for example, by jamming or interference with free and normal operation of the driven parts.

It previously has been proposed to provide mechanism automatically operable in response to overloads, for example in response to heating of a motor or increase in the'electrical power load, for stopping a motor or otherwise interrupting the transmission of power. Generally, such mechanisms have included an undesirable number of parts in addition to the parts required for transmitting power from the motors to the actuated or driven mechanisms, and some have required somewhat delicate control elements such as thermostats or overload current responsive relays.

An object of the present invention is' to provide an improved automatic stop control mechanism which is of sim'plecons'truction and yet is immediate and certain in" operation upon increase of the operating load beyond anormal maximum load.

Another object ofthe invention is to provide an improved mechanism of the character stated which is operable in response toabnorrnal tension in-a flexible driving belt-due to imposition of an abnormal load on an operat ingeleme'nt driven by the belt.

A further objectof the'irtvention is to provide a'power' driven typewriter or'like niaehine'including stop-control meohanism'responsive to tipping'of the-machine for interrupting; the drive.

Other objects of the invention will become apparent from a reading of the following'descriptio'n, theappendedclaims, and the accompanying drawings, in which:

Figure 1- is a-fragmentary sidc'elevational view of an electrictypewriter embodying theinvention,. certain pa'rts at the front of the machine being omitted and others being shown in vertical section;

Figure 2 is afragmentary perspective view showing the mounting of an electric motor, and pulley and belt drive transmitting connections; 7

Figure 3 is a fragmentary vertical section in a" plane extending: fore and aft of the machine'at'the line 3'-3" in Figure 2; and

Figure 4v isa detailed fragmentary vertical sectional view showing a resilientmounting for a'pulley supporting. base, drawn on an enlarged scale.

Mechanism in accordance withthe invention is illustrated'as being embodied in an electric typewriter includinga'frame A ori'which'is mounted a motor B" adapted to drive a'r'otary operating member C through a belt drive mechanism D. The operating'memb'er' C'is'constitute'd" by a snatch'rollof known form journalled'inany suitable manner for'rotation on the main frame'A. The" snatch roll C is adapted t'o'operate' various typewriter ins'tru mentalities" such for example" as the typebars; the case shifting mechanism; the back spacing" mechanism; the

Patented July 31, 1956 2 tabulating mechanism, and the line spacing and carriage returning mechanisms. For the purposes of illustration, the snatch roll C is shown as being operable for actuating a type bar 1 pivoted at 2 in the usual manner on a type bar segment 3, the type bar 1 being swingable clockwise about the pivot 2 to bring its type head into printing position with relation to a cylinder or platen (not shown) supported in the usual manner on a carriage 4- whichis mounted for letter spacing and return travel by means including anti-friction balls 5 arranged to run on a track rail 6 secured to the main frame A.

Mechanism for transmitting power from the snatch roll C to the type bar 1 includes a pawl carrier or actuator 7 pivoted at its rear end at 8 on a lever 9 the lower end-of which is pivoted at 10 on the frame A. A pawl 11 is pivoted at 12 on the actuator 7, and is urged clockwise by a spring 13 interposed between the pawl and the actuator so as to tend to bring the pawl nose 14' into engagement with the match roll. Normally, the pawl 11 is held in theinoperative position shown in Figure 1 by a trigger 15' pivoted at 16' on the actuator 7 and having a nose 17' which engages the pawl nose 14 and holds the latter disengaged from the snatch roll C. A spring 18 interposed between the trigger 15 and the actuator 7 normally main tainsthe trigger in the pawl disabling position.

In order to effect an operation of the type bar 1 by power delivered-by the constantly rotating snatch roll C, akey controlled lever 19 is rocked clockwise so as to move its rear end downwardly and to transmit downward thrust through a flipper 2i) pivoted atj21 on the rear end of the lever 19. The lower end of the flipper 20 is disposed above an ear 22'on the forward end of the trigger 15, the flipper 20 normally being held in such positionby a spring 23 interposed between the flipper and the lever 19 and urging the flipper clockwise to a limit position determined by engagement of a flipper heel or projection 24'with an ear 25 on the lever 19.

In operation, when the rear end of the lever 19 and the flipper 20 are moved downwardly the flipper pushesagainst theear 22" so as to rockthe trigger 15 counterclockwise, thereby elevating: the trigger nose 17 and dis engaging it' from the pawl nose 14. This permits the pawl spnng 13 to rock the pawl 11 clockwise and to bring the-pawl nose 14-into engagement'with the'toothed snatch roll- C which then is rotating constantly in the counterclockwise directionin Figure 1. Consequently the pawl 11 and the actuator 7 will be moved forwardly by the snatchroll,- rocking the lever 9 counterclockwise and pulling forwardly a link 9 'interposed betweenthe top ofthe lever 9 and aheel 1' on the type bar 1. Thiswill move the type bar clockwise about its pivot 2 and into printing position. When themomentum of the actuator 7 and associated-parts throws the pawl nose 14 forwardly and clear of the snatch roll 0 the actuator 7 will be raised or swung clockwise about its pivot 8 and will then be'returned rearwardly by normalizing spring mechanism not shown, thus restoring the parts to their normal positions. The flipper 20 is pivoted and'is spring held as shown in Figure 1 in order to enable the trigger 15 to be returned-to its normal position without interference if the lever 19 is inadvertently held in operative positioninstead of being returned to normal position immediately after being operated.

V The extent to whichthe individual actuator 7 'is driven by the'snatch roll, and'consequently the force of the t'yp ing impact exerted by the associated type'b'ar may be" the trigger 15 'isoper'ated to release the pawl 11; ergag'e ment of the finger 27 with the finger 26 limiting the depth to which the pawl nose 14 may move downwardly into a tooth interspace. By bending one of the fingers 26-27 or otherwise varying the proximity of one to the other when the parts are in their normal or inactive positions as shown in Figure 1 the limiting efiect of the stop finger 26 on the rocking of the pawl 11 may be adjusted.

The present invention relates more particularly to automatic control mechanism for stopping or interrupting the drive to the operating element, in the present instance the snatch roll C. In the illustrated embodiment, the automatic control mechanism is responsive to increase of the load on the driving motor due to jamming of any of the typewriter instrumentalities or other cause for terminating the transmission of power to the snatch roll, and may also be responsive to tipping of the machine in an upwardly-rearwardly direction for interrupting the drive. In the preferred construction, the automatic control mechanism is operable in response to increase in tension in a belt included in a belt drive mechanism generally desig nated D occasioned by abnormal resistance to rotation of the snatch roll C.

The drive transmitting connections between the motor B and the snatch roll C include a series of pulleys and belts for elfecting the required speed reduction in the transmission of drive from the motor to the snatch roll. The motor B is shown as being mounted on an auxiliary base or support 23 by screws 29. The base 2-8 is formed with two end projections or parts 30 and 31 which extend respectively under shelf portions 32 and 33 fixed with re spect to the main frame A and extending inwardly from the side walls thereof toward the center of the machine. The auxiliary base end portions 30 and 31 are suspended from the shelf portions 32 and 33 by screws 34 and 35 which pass through rubber grommets 37 which yieldingly or resiliently connect the base 28 to the main base or frame A in a manner to permit an appreciably although not very great rocking of the base 28 with respect to the fixed base parts 32 and 33.

Fast on the base 28 is an upwardly extending bracket 38 formed at its top end with a boss 39 to which is secured a stub shaft 40 on which is journalled a pair of toothed pulleys 41 and 42 fast with each other so as to rotate together. A toothed belt 43 is trained around the pulley 41 and a toothed pulley 44 on the motor shaft, and a toothed belt 45 is trained around the pulley 42 and a toothed pulley 46 on a shaft 47 on the outer or righthand end of which is secured a three-step toothed pulley 4-8. A carriage return draw band wind-up pulley or drum 49 is mounted on the shaft 4'7 for rotation relative thereto and is adapted to be connected to the shaft 47 for rotation therewith by a clutch mechanism generally desginated 50 which may be of the kind described in more detail in the application of John F. Kloski, Serial No. 341,703, filed March 11, 1953. Since the construction of the clutch mechanism 59 does not in itself affect the operation of the parts in accordance with the present invention, the clutch mechanism is not described herein in more detail.

The stepped pulley 48 constitutes a rotatable driving element for transmitting drive through a toothed belt 51 to a three-step toothed pulley 52 fixed with respect to the snatch roll C, the arrangement being such that the belt 51 can be shifted from pulley step to pulley step to vary the speed of rotation of the operating element or snatch roll C. The belt shifter mechanism, of which a shifter part 53 is shown in Figure 1, may be of the kind shown in the application of Harry L Lambert, Serial No. 459,- 226, filed September 30, 1954.

The snatch roll C and pulley 52 are rotatable on a fixed axis, but the operating pulley 43 is so mounted that although it normally is rotatable about a substantially fixed axis it may shift bodily in response to increased or abnormal tension in the belt 51 occasioned by increased or abnormal resistance to rotation of the snatch roll C, due for example to jamming of parts operable by the snatch roll. When the tension in the belt 51 is increased there is a tendency of the pulley 48 to move toward the front of the machine, and such movement is permitted by the yielding mounting of the base 28 which enables the base and all of the parts mounted thereon to rock from the position shown in full lines in Figure 3 to the position shown in dotted lines in this figure, the rocking taking place about an imaginary axis indicated generally at 54 in Figure 3.

In accordance with the invention, rocking of the pulley 48 toward the front of the machine is utilized for terminating the driving of the snatch roll C. In the construction shown, the termination of the drive is effected by operation of a switch generally designated 55 in circuit with the motor 13. The switch shown is of the kind disclosed and claimed in the application of Harry L. Lambert and William O. Mosher, Serial No. 484,186, filed January 26, 1955, and includes a frame 56 of generally U-shape mounted on the main frame A. Mounted on top of the frame 56 is a stack of insulating laminae 57 which support, in insulated relation, two switch contact arms 58 and 59 connected respectively through conductors 58 and 59 in the motor circuit. An armature 60 is pivoted on the switch frame 56 as at 61 and is urged clockwise as viewed in Figure 2 by a spring 62 so as to hold in elevated position an insulator plate 63 secured to the front of the armature 66 by rivets 64. The plate 63 is formed with a slot 65 through which the front end if the contact arm 58 extends, the arrangement being such that when the plate 63 is in the position shown in Figure 2, and in dotted lines in Figure 3, the contact arm 58 is held out of contact with the companion arm 58, and when the plate 63 is moved downwardly to the position shown in full lines in Figure 3, the contact arm 58 is brought into electrical contact with the arm 59. In this latter position of the arm 58, the motor circuit is closed so that the motor will run and transmit power to the snatch roll C.

Closing of the switch 55 may be effected by manually operable start-stop means including a switch actuating lever 66 pivoted at 67 on the frame A and including a rearwardly extending finger 68 which projects into a slot 69 in the insulator plate 63. When the lever 66 is rocked clockwise from the position shown in Figure 2, and in dotted lines in Figure 3, to the position shown in full lines in Figure 3, the switch arm 58 is moved downwardly as previously explained and the armature 60 is moved close to an electromagnet 70 the winding of which is connected through conductors 71 in circuit with the switch 55. When the switch 55 has been closed and the armature 60 moved close to the electromagnet 70, the latter will releasably hold the armature down against the urge of the spring 62, and will thereby maintain the switch 55 closed.

Manual opening of the switch 55 may be effected by rocking the lever 66 counterclockwise so as to lift the plate 63 against the attraction of the electromagnet 70 on the armature 60 until the contact arm 58 has been separated from the contact arm 59 which will both break the motor circuit and de-energize the electromagnet 70, thus restoring the switch to the control of the spring 62.

Mechanism for opening the switch S5 automatically in response to abnormal tensioning of the belt 51 includes an arm device 72 secured to the auxiliary base 28 by screws 73 and having an car 74 which overlies the switch operating part 66 in front of its pivot 67. The operation of the mechanism may be understood most readily by reference to Figure 3 which shows the parts in full lines in the positions occupied when the switch is closed and the machine is operating under normal conditions. The ear 74 of the arm 72 is in contact or it may be substantially in contact with the lever 66 so that upon rocking of the base 28, the pulley 48, and the other parts mounted on the base to the positions shown in dotted lines in Figure 3, the ear 74 will press upon the lever 66 to rock the latter clockwise to the position shown in dotted lines and thus to lift the insulator plate 63 and move the contact arm 58 away from the contact arm 59". This will interrupt the motor circuit and consequently terminate the transmission of drive to the snatch roll C. If the abnormal resistance to rotation of the snatch roll and the consequent increase of tension in the belt 51 be only temporary, the base 28 and parts supported thereon in .cluding the operating element 48 will return immediately to their normal positions shown in full lines in Figure 3. Nevertheless the switch 55, once having been opened, will be held open by the spring 62 so that the motor B will not begin to run again in response to restoration of the base 28 to, its normal position. Consequently, therewill be no resumed operation of the machine with possible recurrence of the operating difliculty which caused the increase in resistance to rotation of the snatch roll C until after the switch 55 has purposely been closed" by the operator, which should be only after the cause of the shut-off has been determined and corrected.

The preferred construction also is characterized by being responsive to upward-rearward tipping of the machine as a Whole for interrupting the drive to the snatch roll C. Thus if a repairman tips the machine upwardly and inadvertently fails to cut off the power, the switch 55 automatically will be opened during tipping of the machine, and the stopping of the machine having been noticed by the repairman, he will be informed that the manual control for the switch should be set in off position. It nevertheless may be desired to drive the snatch roll when the machine has been tipped to a substantially vertical position so as to enable the repairman to observe the running parts from the bottom of the machine. The positioning of the screws 35 and grommets 3.7 which connect the auxiliary base 28 to thefixedifram'e or base is such that a portion 28 of'the base'ZS member is disposed near the bottom of and projects rearwardly with respect to the main frame when the machine is in a normal or level position and is. resting upon a surface S by means of the usual feet, one of which is shown at 75 in Figure 1. In the normal position of the machine the base portion 28 is disposed a little above the surface S and to the rear of the foot 75. If the machine is tipped upwardly-rearwardly, the base portion 23 will contact the supporting surface S so that the machine weight will be carried through the base 28 along a line extending in a generally forwardly and upwardly inclined direction through the rear part of the base portion 28. This will cause the base 28 to be rocked bodily relatively to the main frame A from the position shown in full lines in Figure 3 to the position shown in dotted lines in this figure, whereupon the arm 72 will coact with the lever 66 in the manner previously explained for opening the cut-off means of switch 55. Thus, the auxiliary base 28 serves as a control member for operating the cut-off switch 55 to terminate effective driving of the operating element or snatch roll C in response to tipping the machine upwardly-rearwardly.

If the machine is tipped further rearwardly so that its bottom will occupy a substantially vertical position in which the base portion 28 is substantially directly under the grommets 37, the weight of the machine will act along a line substantially coincident with or containing the screws 35 and grommets 37 so that there will be no substantial moment imposed on the base 28 tending to rock it from its normal position. Consequently the base 28 and the arm 72 will be returned to their normal positions and the ear 74 will be moved away from the switch operating lever 66, thereby leaving the latter free to be operated manually for starting the motor.

The positioning of the ear 74 of the arm 72 above the manually operable lever 66 is such as to provide a oneway-acting force transmitting connection between the ear and the lever such that the downward movement of the ear 74 will be effective to rock the lever 66 and open the switch 55, but the ear 74 when in normal position will not interfere the manual rocking of the lever 66 for opening the switch and stopping the machine inthe normal manner;

The mechanism shown embodies the invention in ,a' preferred form, but it is intended that the disclosure be illustrative rather than definitive, the invention being defined in the claims.

Wecl'aim:

1. In a' power operated typewriter or like machine;

the combination of a frame; mechanism to be operated supported on said frame; a motor for driving said mech anism and being mounted on said frame; a cut-off means for terminating eifective driving of said mechanism by said motor; a control member; means movably mounting said' control member on said frame adjacent to the bottom and rear of the machine: and normally above th extreme bottom of said frame and to the rear thereof; and means connecting said control member to said" cut-oif means, said control member being contactable With a surface on which said machine rests when said machine-is tipped upwardly-rearwardly whereby said control member is moved and said cutoff means is operated on said'frarne; a member movably mounted on said' frame and beingm'ovable'from a normal position to an olrterat'ed positionin response'to'. tipping of the machine upwardly-rearwardly; and means connecting" saidmember to-said'switch and being operable by said member whenit' is moved from normal position to operated po-' siti'on foropening said switch to stop said'motor.

" 3. In" an electrically" operated typewriter or like'nrachine, the combination of a frame; mechanism to be operated supported on said frame; an electric motor for driving said mechanism and being mounted on said frame; a switch for controlling said motor and being mounted on said frame; a control member; means movably mounting said control member on said frame adjacent to the bottom and rear of the machine and normally above the extreme bottom of the frame and to the rear thereof; and means connecting said control member to said switch, said control member being contactable with a surface on which said machine rests when said machine is tipped upwardly-rearwardly whereby said control member is moved and said switch is operated to stop said motor.

4. In an electrically operated typewriter or like machine, the combination of a frame; a rotatable operating element; a rotatable driving element; an electric motor for driving said driving element; a flexible belt connecting said operating element to said driving element; a switch controlling said motor; means mounting said switch on said frame; means mounting one of said elements on said frame; a support on which the other of said elements is mounted; resilient means mounting said support on said frame so that a portion of said support adjacent to the bottom of the machine projects rearwardly of said frame and is positioned to bear the weight of the machine when it is tipped upwardly-rearwardly, said resilient means being yieldable when the machine is so tipped to permit bodily movement of said support relative to said frame; and means connecting said support to said switch for actuating said switch in response to such bodily movement of said support to stop said motor.

5. In an electrically operated typewriter or like machine, the combination of a frame; a rotatable operating element; a rotatable driving element; an electric motor for driving said driving element; a flexible belt connecting said operating element to said driving element; a switch controlling said motor; means mounting said switch on said frame; means mounting one of said elements on said frame; a support on which the other of said elements is mounted; resilient means mounting said support on said frame so that a portion of said support adjacent to the bottom of the machine projects rearwardly of said frame and is positioned to bear the weight of the machine when it is tipped upwardly-rearwardly, said resilient means being yieldable in response to abnormal tension in said belt due to abnormal resistance to rotation of said operating element and also being yieldable when the machine is tipped to permit bodily movement of said support relative to said frame; and means connecting said support to said switch for actuating said switch in response to such bodily movement of said support to stop said motor.

6. In an electrically operated typewriter or like machine, the combination of a frame; a rotatable operating element; a rotatable driving element; an electric motor for driving said driving element; a flexible belt connecting said operating element to said driving element; a switch controlling said motor; means mounting said switch on said frame; means mounting one of said elements on said frame; a support on which the other of said elements is mounted; resilient means mounting said support on said frame so that a portion of said support adjacent to the bottom of the machine projects rearwardly of said frame and to the rear of said resilientmeans and is positioned to contact a machine supporting surface and to bear the weight of the machine when it is tipped upwardly-rearwardly, said resilient means being yielda'ole when said machine is so tipped to an inclined position and said resilient means is disposed above and in front of said portion of said support to permit bodily movement of said support from its normal position relative to said frame; and means connecting said support to said switch for actuating the latter in response to such bodily movement of said support to stop said motor, said support being restorable to its normal position relative to said frame when said machine is tipped further to the rear to a position in which the portion of said support in contact with said surface is substantially directly under said resilient means, whereby said switch may be operated to start said motor when said machine has been tipped to a substantially vertical position.

7. Automatic control mechanism for a power operated typewriter or like machine including a rotatable operating element, means cooperable with said operating element for actuating a machine instrumentality, a rotatable driving element, an electric motor for operating said driving element, and a flexible belt drivingly connecting said driving element to said operating element, said mechanism comprising means mounting one of said elements for rotation about a normally substantially fixed axis but being yieldable in response to abnormal tension in said belt occasioned by abnormal resistance to rotation of said operating element to permit said one of said elements to shift bodily under the influence of such increased belt tension; a switch controlling said motor; a spring urging said switch to open position; electromagnetic means energized by closing of said switch for releasably maintaining said'switch in closed position; and means responsive to the aforesaid bodily shifting of said one of said elements for opening said switch against the action of said electromagnetic means to de-energize said electromagnetic means, restore said switch to the opening influence of said spring and stop said motor.

References Cited in the file of this patent UNITED STATES PATENTS 

